Spherical porous carbon, silicon-carbon composite material, preparation method and application of spherical porous carbon and silicon-carbon composite material, and battery

Abstract

The invention discloses spherical porous carbon, a silicon-carbon composite material, a preparation method and application of the spherical porous carbon and the silicon-carbon composite material, and a battery. The preparation method of the spherical porous carbon comprises the following steps: (1) grinding vinasse, and performing hydrothermal reaction in a slightly acidic aqueous solution to obtain vinasse carbon microspheres; (2) pre-carbonizing the vinasse carbon microspheres to obtain pre-carbonized microspheres; and (3) calcining the mixture of the pre-carbonized carbon microspheres and alkali under the protection of inert gas, washing, and drying to obtain the spherical porous carbon. According to the preparation method, pollution-free treatment and high-added-value utilization of the vinasse can be achieved, high-uniformity spherical porous carbon can be obtained without depending on a granulation process, and the preparation method has the advantages of being efficient, environmentally friendly, green, capable of saving energy and the like; the spherical silicon-carbon negative electrode material prepared from the spherical porous carbon has high compaction density and high capacity, and also has excellent electrochemical performance when being applied to batteries.

Description

Technical Field

[0001] The present invention belongs to the field of new energy materials, and specifically relates to a spherical porous carbon, silicon-carbon composite material, a preparation method thereof, an application thereof, and a battery. Background Art

[0002] With the rapid development of consumer electronics, electric vehicles, and electrochemical energy storage, the demand for high-energy-density lithium-ion batteries is becoming increasingly urgent. Traditional graphite anode materials are unable to meet current application requirements due to their limited theoretical specific capacity. Elemental silicon has attracted widespread attention from researchers and industry due to its abundant reserves on Earth, theoretical specific capacity of up to 4200mAh / g, and high lithium insertion potential. However, during the lithium insertion process, silicon anode materials undergo significant volume expansion, which not only causes material pulverization but also leads to loss of active materials, thereby causing performance degradation over multiple cycles. At the same time, the formation of a solid electrolyte interface (SEI) can also cause capacity loss. From the perspective of commercial applications, the silicon anode material industry is constantly tackling key challenges. Its main technological development path has evolved from sand-milled silicon-carbon, conventionally coated silicon-oxygen, pre-lithium and pre-magnesium silicon-oxygen, to the current vapor-deposited silicon-carbon. Despite continuous technological iterations, the fourth-generation vapor-deposited silicon-carbon technology still faces many challenges.

[0003] The preparation of porous carbon frameworks is crucial in vapor-phase deposition silicon-carbon technology. As the substrate for silicon deposition, the porous carbon framework not only needs to have a porous structure to accommodate silicon but also possess a certain degree of structural stability to cope with the volume expansion of silicon during charging and discharging, and to ensure batch stability. Spherical porous carbon structures offer unique advantages in terms of morphology. Their spherical shape imparts good fluidity and filling properties to the material. During electrode preparation, they enable more uniform dispersion, reduce porosity and defects within the electrode, and increase the electrode's compaction density, thereby enhancing the battery's volumetric energy density. Traditional methods for preparing spherical structures, such as spray granulation, suffer from complex processes, high costs, and high energy consumption. Spray granulation requires specialized equipment to atomize the material into tiny droplets, which are then dried in hot air to form granules. This entire process not only requires large equipment investments but also places extremely stringent control requirements on process parameters. Therefore, the development of efficient, low-cost, and high-performance spherical porous carbon and silicon-carbon anode material preparation technologies is urgent. Summary of the Invention

[0004] The present invention is precisely to solve the above-mentioned technical problems and provides a spherical porous carbon, silicon-carbon composite material and its preparation method, application and battery. The preparation method of the spherical porous carbon in the present invention can achieve pollution-free treatment and high value-added utilization of wine lees and has great potential in breaking through the limitations of the existing spherical structure preparation process. It can obtain highly uniform spherical porous carbon without relying on the granulation process, and has the advantages of high efficiency, environmental protection, greenness and energy saving. It has opened up a new path for the development of negative electrode materials for lithium-ion batteries and is expected to play an important role in the future energy storage field. The spherical silicon-carbon negative electrode material prepared from the spherical porous carbon has a high compaction density and high capacity, and also exhibits excellent electrochemical performance when used in lithium-ion batteries.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] The present invention provides a method for preparing spherical porous carbon, which comprises the following steps:

[0007] (1) grinding the vinasse and performing a hydrothermal reaction in a slightly acidic aqueous solution to obtain vinasse carbon microspheres;

[0008] (2) pre-carbonizing the wine lees carbon microspheres to obtain pre-carbonized microspheres;

[0009] (3) calcining the mixture of the pre-carbonized carbon microspheres and alkali under the protection of an inert gas, and then washing and drying the mixture to obtain the spherical porous carbon.

[0010] In step (1), the wine lees may be one or more of white wine lees, beer lees, yellow rice wine lees, and grape wine lees. The lees are generally dried before use. The moisture content of the dried lees is preferably less than 5%.

[0011] In step (1), the grinding method can be mechanical grinding or manual grinding, preferably mechanical grinding.

[0012] The mechanical grinding is generally ball milling, for example, in a planetary ball mill. During the mechanical grinding process, the ratio of the revolution speed to the rotation speed can be 1: (1-3), for example, 1: 1.5. The revolution speed can be 150-500 rpm, for example, 200 rpm, 250 rpm, 300 rpm or 400 rpm. The rotation speed can be 200-800 rpm, for example, 300 rpm, 400 rpm, 450 rpm or 600 rpm. rpm. The mechanical grinding time can be 10-90 min, for example 30 min, 45 min, 50 min,60min or 90min. During the mechanical grinding process, the diameter of the grinding beads used can be 1-40mm, such as 5mm, 8mm, 10mm or 20mm. During the mechanical grinding process, the ball-to-material ratio can be (2-15):1, such as 3:1, 4:1, 5:1, 6:1, 8:1 or 10:1, and the ball-to-material ratio refers to the mass ratio of the grinding beads to the material to be ground. The revolution speed generally refers to the speed of the grinding drum (or grinding bowl) of the planetary ball mill when it is driven by the main shaft (or turntable) and moves in a circular motion around a center point; the rotation speed generally refers to the speed at which the grinding drum itself rotates around its axis while in revolution, that is, the rotation speed.

[0013] The manual grinding generally refers to manual grinding using a mortar.

[0014] In step (1), the pH of the slightly acidic aqueous solution is generally 4.0-6.9, for example 5.5, 6.0 or 6.5. According to conventional practice in the art, an acid is generally added to deionized water to prepare the slightly acidic aqueous solution. The acid in the slightly acidic aqueous solution can be a strong acid and / or a weak acid conventional in the art, generally one or a combination of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, acetic acid and carbonic acid.

[0015] In step (1), the hydrothermal reaction generally refers to a process in which water as a solvent reacts chemically with other substances at a certain temperature and pressure in a closed system such as an autoclave. According to conventional practice in the art, the reaction solvent of the hydrothermal reaction is generally deionized water. The mass ratio of the vinasse to the slightly acidic aqueous solution can be 1:(1-5), for example 1:2, 1:3 or 1:4.

[0016] In step (1), the temperature of the hydrothermal reaction may be 100-220° C., for example, 120° C., 130° C., 140° C., 150° C., 160° C., 180° C., or 200° C. The time of the hydrothermal reaction may be 2-10 h, for example, 2 h, 3 h, 5 h, or 8 h.

[0017] In step (1), according to conventional practice in the art, washing and drying are generally required after the hydrothermal reaction. The washing and drying conditions may be conventional in the art. The solvent used for the washing may be ethanol and / or deionized water. The number of washings is generally 3-5 times. The drying temperature may be 80-100° C., for example, 80° C. The drying time may be 6-24 hours, for example, 12 hours.

[0018] In step (2), according to conventional practice in the art, the pre-carbonization is generally performed in a tube furnace under the protection of an inert gas, such as argon or nitrogen.

[0019] In step (2), the pre-carbonization temperature is preferably 400-700° C., such as 420° C., 450° C., 500° C., 600° C., 650° C., or 680° C. The pre-carbonization time is preferably 2-6 h, such as 2 h, 2.5 h, 3 h, or 4 h.

[0020] In step (3), according to the conventional art, the inert gas is, for example, argon or nitrogen. The calcination can be carried out in a muffle furnace or a tube furnace.

[0021] In step (3), the base may be one or more of sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium carbonate and potassium bicarbonate.

[0022] In step (3), the mass ratio of the pre-carbonized microspheres to the base may be (0.3-5):1, preferably (0.5-3):1, for example, 0.5:1, 0.8:1, 1:1, 1.5:1 or 2:1.

[0023] In step (3), the calcination temperature may be 450-1100°C, for example, 500°C, 550°C, 600°C, 700°C, 800°C, 900°C, 1000°C or 1050°C; the calcination time may be 3-12h, for example, 3h, 4h, 6h, 8h or 10h.

[0024] In step (3), according to the conventional practice in the art, washing, drying and screening are generally required after the calcination is completed. The conditions for the washing and the drying can be conventional in the art. The solvent used for the washing can be ethanol and / or deionized water, and the washing is generally required to a pH < 9. The drying is generally carried out in a vacuum drying oven, the drying temperature can be 80-100°C, and the drying time can be 6-24h, for example 10h or 12h. The mesh size of the sieve used for the screening can be 100-400 mesh, for example 200 mesh.

[0025] The present invention also provides a spherical porous carbon prepared by the above-mentioned preparation method.

[0026] The present invention also provides a method for preparing a silicon-carbon composite material, which comprises the following steps:

[0027] The spherical porous carbon as described above is subjected to silane deposition to obtain a silicon-carbon composite material.

[0028] In the present invention, the spherical porous carbon generally needs to be activated before use. The activation process preferably includes the following steps: acid washing the spherical porous carbon, followed by drying, vacuum degassing, and heating.

[0029] Wherein, the amount of acid used in the pickling process can be conventional in the art, generally enough to immerse the spherical porous carbon. The acid used in the pickling can be hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid or acetic acid. The concentration of the acid used in the pickling can be 0.1-5M, for example, 0.5M, 1M or 2M. The pickling time can be 20-60min, for example, 30min, 40min or 50min. The pickling is generally carried out in a mixed state (for example, ultrasonic or stirring). After the pickling, it is generally necessary to wash with deionized water until neutral.

[0030] In some specific embodiments, the acid washing process is performed by ultrasonic treatment with 0.5 M dilute hydrochloric acid for 50 min.

[0031] The drying is generally carried out in an oven at a temperature of 80-100° C. and for a time of 2-12 hours, for example, 6 hours.

[0032] The vacuum degassing generally needs to be evacuated to below 5×10-3Pa.

[0033] The heat treatment is generally performed under an inert atmosphere (e.g., argon). The heat treatment is generally performed in a tube furnace. The calcination temperature may be 300-500°C, for example, 400°C. The calcination time may be 0.5-4 hours, for example, 1 hour or 2 hours. According to conventional practice in the art, after the heat treatment, the temperature may be directly raised to the silane deposition temperature for silane deposition without cooling down.

[0034] In the present invention, the temperature of the silane deposition may be 400-600° C., such as 500° C. or 550° C. The time of the silane deposition may be 1-4 hours, such as 1 hour or 2 hours.

[0035] In the present invention, the silane deposition is preferably performed in a mixture of silane and an inert gas. The silane deposition is generally performed in a tube furnace. The silane flow rate is preferably 10-50 sccm, for example, 20 sccm, 25 sccm, or 30 sccm. The inert gas flow rate is preferably 50-200 sccm, for example, 100 sccm, 120 sccm, or 150 sccm.

[0036] The total pressure of the mixed gas may be 100-2000 Pa, such as 200 Pa or 500 Pa.

[0037] In a specific embodiment, during the silane deposition process, the silane flow rate is 20 sccm and the argon flow rate is 100 sccm.

[0038] The present invention also provides a use of the aforementioned spherical porous carbon or silicon-carbon composite material in a battery, preferably a lithium-ion battery.

[0039] The present invention also provides a battery comprising a positive electrode, a negative electrode, an electrolyte and a separator, wherein the negative electrode comprises the spherical porous carbon or silicon-carbon composite material as described above. The battery is preferably a lithium-ion battery.

[0040] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0041] The reagents and raw materials used in the present invention are commercially available.

[0042] The positive progress effect of the present invention is:

[0043] The present invention directly prepares spherical porous carbon from wine lees biological waste, which is difficult to utilize as a resource. It does not rely on spray granulation and mechanical granulation processes, breaking through the limitations of the preparation process of traditional porous carbon spherical structures. The preparation method has the advantages of high efficiency, environmental protection, greenness, and energy saving. The spherical silicon-carbon negative electrode material prepared from the spherical porous carbon has uniform morphology, high compaction density and high capacity, and also exhibits excellent electrochemical performance when used in lithium-ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the SEM image of the wine lees carbon microspheres prepared in Example 1;

[0045] Figure 2 This is the SEM image of the pre-carbonized microspheres prepared in Example 1;

[0046] Figure 3 This is an SEM image of the spherical porous carbon material prepared in Example 1;

[0047] Figure 4 This is the SEM image of the porous carbon prepared in Comparative Example 2. DETAILED DESCRIPTION

[0048] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0049] Example 1

[0050] (1) Pretreatment of wine lees: Select white wine lees (Sichuan Zhengyu), place them in an electric blast drying oven, dry them at 80°C until the moisture content is less than 5%, select QM-3SP4 model planetary ball mill, use zirconia balls with a diameter of 10mm as grinding media, match the balls with a ball-to-material ratio of 8:1 and seal them, rotate at 300rpm and 450rpm, and ball mill for 1 hour. Add oxalic acid to deionized water to prepare a slightly acidic aqueous solution with a pH of 6, mix the ball-milled wine lees with the slightly acidic aqueous solution at a mass ratio of 1:3, put them into a reactor and perform hydrothermal reaction at 160°C for 6 hours. After the reaction, filter the product to remove the solvent and then wash it with deionized water and ethanol several times to remove impurities. Finally, dry it in a vacuum drying oven at 80°C for 12 hours to obtain wine lees carbon microspheres.

[0051] (2) Pre-carbonization: The obtained wine lees carbon microspheres were placed in a tube furnace, and under nitrogen protection, the temperature was increased to 500°C at a heating rate of 5°C / min, and this temperature was maintained for 3 hours for pre-carbonization to obtain pre-carbonized microspheres;

[0052] (3) Alkali etching to form pores, washing, and screening: The pre-carbonized microspheres were mixed with potassium hydroxide in a mass ratio of 2:1. Under nitrogen protection, the mixture was placed in a muffle furnace and heated to 800°C at a heating rate of 10°C / min. This temperature was maintained for 3 hours for calcination. After calcination, it was naturally cooled to room temperature. The product was washed with deionized water several times until the pH of the washing solution was <9, and then dried in a vacuum drying oven at 100°C for 10 hours. Finally, it was sieved with a sieve with a mesh size of 200 to obtain a spherical porous carbon material.

[0053] Example 2

[0054] Compared with Example 1, except that the hydrothermal temperature in step (1) is adjusted to 120° C., the other operations and conditions are the same as those in Example 1.

[0055] Example 3

[0056] Compared with Example 1, except that the hydrothermal temperature in step (1) is adjusted to 140° C., the other operations and conditions are the same as those in Example 1.

[0057] Example 4

[0058] Compared with Example 1, except that the hydrothermal time in step (1) was adjusted to 2 h, the other operations and conditions were the same as those in Example 1.

[0059] Example 5

[0060] Compared with Example 1, except that the pre-carbonization time in step (2) is adjusted to 2 hours, the other operations and conditions are the same as those in Example 1.

[0061] Example 6

[0062] Compared with Example 1, except that the temperature of the pre-carbonization in step (2) is adjusted to 420° C., the other operations and conditions are the same as those in Example 1.

[0063] Example 7

[0064] Compared with Example 1, except that the temperature of the pre-carbonization in step (2) is adjusted to 680° C., the other operations and conditions are the same as those in Example 1.

[0065] Example 8

[0066] Compared with Example 1, except that the carbonization temperature in step (3) is adjusted to 500° C., the other operations and conditions are the same as those in Example 1.

[0067] Example 9

[0068] Compared with Example 1, except that the carbonization temperature in step (3) is adjusted to 600° C., the other operations and conditions are the same as those in Example 1.

[0069] Example 10

[0070] Compared with Example 1, except that the carbonization temperature in step (3) is adjusted to 1050°C, the other operations and conditions are the same as those in Example 1.

[0071] Example 11

[0072] Compared with Example 1, except that the mass ratio of pre-carbonized microspheres to potassium hydroxide in step (3) was adjusted to 0.5:1, the other operations and conditions were the same as those in Example 1.

[0073] Example 12

[0074] Compared with Example 1, except that the mass ratio of pre-carbonized microspheres to potassium hydroxide in step (3) was adjusted to 1:1, the other operations and conditions were the same as those in Example 1.

[0075] Example 13

[0076] Compared with Example 1, except that the ball-to-material mass ratio in step (1) is adjusted to 3:1, the other operations and conditions are the same as those in Example 1.

[0077] Example 14

[0078] Compared with Example 1, except that the mass ratio of the balls and materials in step (1) is adjusted to 5:1, the other operations and conditions are the same as those in Example 1.

[0079] Example 15

[0080] Compared with Example 1, except that the ball mill speed in step (1) was adjusted to 200 rpm for revolution and 300 rpm for rotation, the other operations and conditions were the same as those in Example 1.

[0081] Example 16

[0082] Compared with Example 1, except that the white wine lees in step (1) was replaced with beer tank (brand: Chinachem), the other operations and conditions were the same as those in Example 1.

[0083] Comparative Example 1

[0084] Compared with Example 1, except that ball milling mixing is not performed in step (1), the other operations and conditions are the same as those in Example 1.

[0085] Comparative Example 2

[0086] Compared with Example 1, except that hydrothermal treatment is not performed in step (1), the remaining operations and conditions are the same as those in Example 1.

[0087] Comparative Example 3

[0088] Compared with Example 1, except that the pre-carbonization treatment in step (2) is not performed, the other operations and conditions are the same as those in Example 1.

[0089] Effect embodiment

[0090] (1) SEM test

[0091] Figure 1 This is the SEM image of the wine lees carbon microspheres prepared in Example 1; Figure 2 This is the SEM image of the pre-carbonized microspheres prepared in Example 1; Figure 3 This is an SEM image of the spherical porous carbon material prepared in Example 1;

[0092] Figure 4 This is the SEM image of the porous carbon prepared in Comparative Example 2. Figure 3 and Figure 4 It can be seen that the porous carbon material particles prepared in Example 1 are spherical and uniform in shape, while the porous carbon prepared in Comparative Example 2 has an irregular morphology.

[0093] (2) Material physical and electrochemical performance testing

[0094] The porous carbon materials prepared in Examples 1 to 16 and Comparative Examples 1-3 were respectively subjected to compaction density tests using a powder compaction density tester (CDCT-4100). Silane deposition was then performed to prepare a silicon-carbon composite material, and the preparation method was as follows: first, the porous carbon material was immersed in 0.5M dilute hydrochloric acid and ultrasonically treated for 50 minutes (power 200W), then rinsed with deionized water until neutral and dried at 100°C for 6 hours, then placed in a tube furnace for vacuum degassing, argon gas (flow rate 100sccm) was introduced, and the temperature was raised to 400°C and kept warm for 1 hour; then the temperature was continued to be raised to 550°C and silane deposition was performed in a mixed gas of silane and argon, with a silane flow rate of 20sccm, an argon flow rate of 100sccm, a total pressure of 200Pa, and a deposition time of 120 minutes. After deposition, the material was sealed and stored in a glove box.

[0095] The electrochemical test method is as follows: the silicon-carbon composite material, conductive carbon black and sodium carboxymethyl cellulose prepared above are mixed in a mass ratio of 80:10:10, deionized water is added to prepare the slurry, and the mixture is coated on a 10 μm thick copper foil. After vacuum drying at 120°C for 12 hours, the electrode sheet with a diameter of 12 mm is punched out. The active substances on the electrode sheet are The mass loading is 3.0 mg / cm 2 ; The negative electrode is metallic lithium, and the electrolyte is LB-048 electrolyte (Duoduo Chemical) assembled CR2032 button cells in an argon glove box and performed constant current charge / discharge tests on a LAND CT2001A battery test system. The test voltage range was 0.01–1.5 V (vs. Li / Li+) and the current density was 0.1 C (1 C = 2000 mA / g). The test results are shown in Table 1:

[0096] Table 1

[0097]

[0098] According to the results in Table 1, the silicon-carbon composite material prepared by the spherical porous carbon material prepared by the present invention has excellent compacted density, discharge specific capacity and cycle life. Comparing Example 1 with Comparative Example 1, it can be seen that due to the lack of ball milling, the lees particles are difficult to fully decompose, dehydrate, crack and polymerize under the hydrothermal reaction, the particles have poor mechanical properties, loose structure, and low compacted density and capacity. Comparing Example 1 with Comparative Example 2, it can be seen that due to the lack of a hydrothermal treatment process, the lees cannot form a spherical structure, and it is difficult to achieve the performance of spherical porous carbon. Comparing Example 1 with Comparative Example 3, it can be seen that due to the lack of pre-carbonization, the pore structure of the lees is not stable, and it is easily destroyed in alkali etching, which weakens the performance of the porous carbon.

[0099] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A method for preparing spherical porous carbon, characterized in that: It includes the following steps: (1) grinding the vinasse and performing a hydrothermal reaction in a slightly acidic aqueous solution to obtain vinasse carbon microspheres; (2) pre-carbonizing the wine lees carbon microspheres to obtain pre-carbonized microspheres; (3) calcining the mixture of the pre-carbonized carbon microspheres and alkali under the protection of an inert gas, and then washing and drying the mixture to obtain the spherical porous carbon.

2. The method for preparing spherical porous carbon according to claim 1, wherein: Step (1) satisfies one or more of the following conditions: (1) The wine vat is one or more of a white wine vat, a beer vat, a yellow wine vat, and a grape wine lees; (2) The grinding method is mechanical grinding or manual grinding, preferably mechanical grinding; During the mechanical grinding process, the ratio of the revolution speed to the rotation speed is preferably 1:(1-3); the revolution speed is preferably 150-500 rpm; the rotation speed is preferably 200-800 rpm; the mechanical grinding time is preferably 10-90 min; the diameter of the grinding beads used in the mechanical grinding process is preferably 1-40 mm; the ball-to-material ratio during the mechanical grinding process is preferably (2-15):1; (3) the pH of the slightly acidic aqueous solution is 4.0-6.9, for example, 5.5, 6.0 or 6.5; (4) the mass ratio of the vinasse to the slightly acidic aqueous solution is 1:(1-5); (5) The acid in the slightly acidic aqueous solution is a strong acid and / or a weak acid, preferably one or a combination of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, acetic acid and carbonic acid; (6) The temperature of the hydrothermal reaction is 100-220°C, for example, 120°C, 130°C, 140°C, 150°C, 160°C, 180°C or 200°C; (7) The hydrothermal reaction time is 2-10 h, for example, 2 h, 3 h, 5 h or 8 h.

3. The method for preparing spherical porous carbon according to claim 1, wherein: In step (2), the pre-carbonization temperature is 400-700°C, for example, 420°C, 450°C, 500°C, 600°C, 650°C or 680°C; In step (2), the pre-carbonization time is 2-6 hours, for example, 2 hours, 2.5 hours, 3 hours or 4 hours.

4. The method for preparing spherical porous carbon according to claim 1, wherein: Step (3) satisfies one or more of the following conditions: (1) The alkali is one or more of sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium carbonate and potassium bicarbonate; (2) The mass ratio of the pre-carbonized microspheres to the base is (0.3-5):1, preferably (0.5-3):1, for example, 0.5:1, 0.8:1, 1:1, 1.5:1 or 2:1; (3) the calcination temperature is 450-1100°C, for example, 500°C, 550°C, 600°C, 700°C, 800°C, 900°C, 1000°C or 1050°C; (4) The calcination time is 3-12 hours, for example, 3 hours, 4 hours, 6 hours, 8 hours or 10 hours.

5. Spherical porous carbon prepared by the method for preparing spherical porous carbon according to any one of claims 1 to 4.

6. A method for preparing a silicon-carbon composite material, characterized in that: It includes the following steps: The spherical porous carbon as claimed in claim 5 is subjected to silane deposition to obtain a silicon-carbon composite material.

7. The method for preparing the silicon-carbon composite material according to claim 6, wherein: The preparation method satisfies one or more of the following conditions: (1) The spherical porous carbon needs to be activated before use; The activation treatment process preferably includes the following steps: pickling the spherical porous carbon, drying, vacuum degassing, and heating; the acid used in the pickling is preferably hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid, or acetic acid; the concentration of the acid used in the pickling is preferably 0.1-5M; the pickling time is preferably 30-60 minutes; the temperature of the heating treatment is preferably 300-500°C; and the heating time is preferably 0.5-4 hours; (2) The temperature of the silane deposition is 400-600° C.; (3) The silane deposition time is 1-4 hours; (4) The silane deposition is carried out in a mixed gas of silane and an inert gas.

8. A silicon-carbon composite material obtained by the method for preparing a silicon-carbon composite material according to claim 6 or 7.

9. Use of the spherical porous carbon according to claim 5 or the silicon-carbon composite material according to claim 8 in a battery.

10. A battery, characterized in that: The invention comprises a positive electrode, a negative electrode, an electrolyte and a separator, wherein the negative electrode comprises the spherical porous carbon according to claim 5 or the silicon-carbon composite material according to claim 8.

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